**5. Exposure to foods contaminated with chemical pesticides: overview of the public health concerns**

Pesticide use has been closely associated with human poisonings and their related illnesses and has been long seen as a severe public health problem. The potential toxicity in pesticides has caused both acute and chronic health effects, depending on the quantity and ways in which the person is exposed (**Figure 1**).

The tenacious and pervasive nature of several pesticides used in agriculture and other carbon-based pollutants has posed chaos to mankind as a result of their high toxicity and potentials to bio-accumulate [28]. These chemical pesticides are identified to impede the usual effectiveness of reproductive and endocrine systems in living organisms [29]. Several pesticides such as dichlorodiphenyltrichloroethane (DDT), chlordane, aldrin, dieldrin, endrin, mirex, heptachlor, and hexachlorobenzene influence lethal effects on the health of human and the environment [28]. In the year 1990, a task force of the World Health Organization (WHO) estimated that about one million unintentional pesticide poisonings occur naturally, leading to approximately 20,000 deaths. There are also an estimated 385 million cases of unintentional acute pesticide poisoning UAPP occur manually worldwide including 11,000 fatalities. This estimation depends on the quality and validity of data as well as the estimation procedure [30].

In most regions of the world, the condition is even worse. Approximately 80% of the pesticides produced per annum in the world are used in developed countries [12], but less than half of all pesticide-induced deaths occur in these countries [31]. Increased proportion of pesticide poisonings and mortality occur in developing countries where there are insufficient occupational safety standards and regulations in its use on foods; insufficient enforcement; poor labelling of pesticides; illiteracy; and deficient knowledge of pesticide [31]. Moreover, usual pesticide residue levels in food are often higher in developing countries than in the developed countries. For example, a study in Egypt reported that most of assayed milk samples, when tested for fifteen

#### **Figure 1.**

*Sources of chemical pesticide contamination in human foods [28].*

different pesticides, contained residue levels between 60% and 80% [32]. By way of contrast, 50% of the milk samples analyzed in a US milk study had pesticide residues, all in trace quantities well below EPA and FDA regulatory limits [33].

Detectable levels of chemical pesticide residues are seen in about 35% of the foods purchased by consumers possess [34, 35]. Between 1 and 3% of these foods possess chemical pesticide residue levels that are beyond the permissible tolerance level [34]. Considering the analytical methods used in the developing countries, the residue levels may even be higher due to the reasons that they may detect just about one-third of the chemical pesticides in use. The rate of contamination is undoubtedly higher for fruits and vegetables because these foods receive the highest dosage of pesticides. One USDA study has shown that some pesticide residue remains in fruits and vegetables even after they have been washed, peeled, or cored [36]. Consequently, there are many justifiable reasons why 97% of the public is concerned about pesticide residues in its food [31].

All over the world, apart from exposure via contaminated food, pesticide exposure at the highest levels are found in farm workers, pesticide applicators, and people who live adjacent or very close to heavily treated agricultural land. Due to the fact that farmers and farm workers directly handle 70–80% of the pesticides they use, they are at the greatest risk of exposure [31, 37]. The epidemiological evidence suggests a significantly higher rate of cancer incidence among farmers and farmworkers in the US and Europe than among non-farm workers in some areas [34, 38]. In these high-risk populations, there is strong evidence for associations between lymphomas and soft-tissue sarcomas as well as between lung cancer and exposure to organochlorine insecticides [27].

Consequently, both the acute and chronic health effects of pesticides warrant attention and concern especially as it was used in farm food production and its storage. While the acute toxicity of most pesticides is well documented [39], there is no sound information on chronic human illnesses such as cancer. Though based on animal studies, the International Agency for Research on Cancer found "sufficient" evidence of carcinogenicity in eighteen pesticides and "limited" evidence in an additional sixteen pesticides [28]. However, some studies found no significant difference in non-Hodgkin's lymphoma mortality between farmers and non-farmers. In addition, [31] estimates that fewer than 1% of the human cancer cases in the US are attributable to pesticide exposure via food or otherwise. With the increasing number of cancer cases annually, [31, 40] assessment indicates that chemical pesticides causes less than 12,000 cases of cancer per year.

Studies with proven confirmation have also suggested that many severe and chronic conditions are linked with the use chemical pesticide [41]. For example, in an animal studies, dibromochloropropane (DBCP), the proscribed pesticide used for plant pathogen control, was found to cause testicular dysfunction [42] and was linked to infertility in human workers who had been exposed to the chemical [43]. Also, a large body of evidence obtained from animal studies suggests that pesticides can produce immune dysfunction [44]. In a study of women who had chronically ingested groundwater contaminated with low levels (mean of 16.6 ppb) of aldicarb, [44] reported evidence of significantly reduced immune response, although these women did not exhibit any overt health problems.

There is also growing evidence of sterility in humans and various other animals, particularly in males, due to various chemicals and pesticides they ingest through contaminated food and in the environment [45]. Sperm counts in Europe have reduced by about 50% and continue to decrease an additional 2% per year. In the study of [46], young male river otters in the lower Columbia River and male alligators in Florida's Lake Apopka have smaller reproductive organs than males in unpolluted regions of their respective habitats.

#### *Chemical Pesticides and Food Safety DOI: http://dx.doi.org/10.5772/intechopen.102395*

Even though it is habitually challenging to evaluate the influence of individual chemical pesticides, the serious health issues associated with organophosphorus related pesticides which have basically substituted the proscribed organochlorines are of specific interest [39]. The malady Organophosphate Induced Delayed Polyneuropathy (OPIDP) is well studied, reported, documented and is manifested by irreversible neurological defects. The deterioration of memory, moods, and the capacity for abstract thought has been observed in some cases [47], while other cases indicate that persistent neurotoxic effects may result even after the termination of an acute organophosphorus poisoning incident [39].

Chronic conditions such as OPIDP constitute an important public health issue because of their potential cost to society. For example, the effect of pesticides on children has become a growing concern [48]. Children can be exposed to pesticides daily through the foods they eat [31]. Considering the increased understanding of the distinctive biological differences between children and adults, it has shown noticeably that the current chemical pesticide acceptability level and the system of regulation, as it concerns children, is sternly lacking. Majority of the regulations are based on adult acceptability level and tolerances. Biologically, it is known that children's metabolic rates are higher than adults, and their capability to stimulate, detoxify, and excrete compounds that are xenobiotic in nature is dissimilar from that of adults. Also, considering of their slighter bodily size, children are exposed to increased levels of chemical pesticides per unit of body weight. Indication of this is seen in a study of [49] which reported that 50% of England and Wales pesticide poisonings involved children of or under the age of ten [49]. In general, the realization that children's sensitivities to toxins are much different than those of adults has provided the impetus for the movement towards setting specific pesticide regulations especially the level of residues in food with children in mind [36].
